Before we get to specific foods whose toxicity levels change when heated or reheated, let’s go over the basics you will want to keep in mind to avoid cooking-related toxins in general:

Ditch the Microwave

Today, 90% of all American homes have a microwave oven and remain unaware of the risk. I know how convenient cooking with a microwave can be.

However, a study conducted by the University of Vienna almost thirty years ago linked microwaving to nerve damage and lowered kidney function. Other studies have connected it to a drastic reduction in liposome activity, needed to inhibit harmful bacterial growth.

Never Use Saran Wrap, Plastic Ware, or Styrofoam to Reheat Food

If you must use the microwave, NEVER use containers or lids that are made of plastic in any form. Plastic cookware and coverings release a variety of harmful substances when heated.

Two of the most toxic substances are polyethylene terephthalate (PET) and biphenol A (BPA). BPA is a xenoestrogen that has been directly linked to breast cancer. Styrofoam contains styrene, which the International Agency for Research on Cancer has deemed a “probably cancer agent.”

Don’t Use Teflon Cookware

The main ingredient in most non-stick surfaces is polytetrafluoroethylene (PTFE), which has been labeled as “likely to be carcinogenic to humans” by the EPA.

Dupont’s Teflon also contains PFOA (C8). Studies show a correlation between PFOA and immune system issues, thyroid issues, pancreatic cancer and breast cancer. Approximately 98% of the population of the U.S. has some level of non-biodegradable PFOA in their bloodstream.

Stay Away From Aluminum Foil

Using aluminum foil as a cover or container for heating foods (and using aluminum cookware in general) releases this substance into the food. Aluminum exposure has been linked to neurological issues and long-term exposure has been linked to Alzheimer’s, autism and ADHD.

When we eat these veggies raw, the bacteria in our mouth convert these nitrates into nitrites, which are then stored in the cells until they are needed in the form of nitric oxide, a natural anti-inflammatory that can calm blood vessels and help to increase blood flow.

The heating process converts nitrate in veggies into nitrites before they enter your mouth; each time you reheat them, they become a little more toxic. Because of this, the best way to eat celery, carrots, spinach and beets are organic, raw and as fresh as can be!

2. High-Protein Foods

Eggs, chicken, and even mushrooms are all protein powerhouses but these proteins begin to deteriorate as soon as you cook them. The protein composition of chicken in particular, which contains a higher protein content than red meat, changes when it goes from cold to hot the second time around. All this puts added strain on your digestive system.

The best bet for these kinds of foods is to only cook up what you think you will consume in the first sitting. If you must reheat chicken, make sure it is very hot through and through. Eggs and mushrooms, in particular, are vulnerable to microorganisms. It is best to never reheat them at all.

3. Rice

Cooked rice of any variety stored in the fridge improperly may be at risk of developing bacterial spores that can cause food poisoning. This is especially true if the rice is left to sit at room temperature because it can lead to rapid spore multiplication which can cause severe digestive upset and even poisoning. If you do reheat rice, be sure it has been stored properly in an airtight container.

4. Potatoes

Potatoes should be avoided or eaten in moderation if one is on a healthy breast protocol because of their high sugar content. That being said, cooked potatoes do contain vital nutrients such as vitamin B6, potassium, and even vitamin C.

When cooked potatoes are left at room temperature, however, or are slow-cooked a second time, they can turn toxic. Warm temperatures can promote the growth of botulism in potatoes so always refrigerate them immediately and throw away anything that has potatoes in it after a couple of days.

5. Oils

Certain oils have very low tolerance to heat and will even turn carcinogenic the first time you cook with them. These include grape seed oil, hazelnut oil, and flax seed oil. When you reheat these kinds of oils a second time, they will become rancid. Never use these oils for baking or cooking. Instead, consume them fresh, drizzled on top of a salad, steamed veggies or organic meats.

Consuming fried foods when dining out is never recommended under any circumstances. This is because most restaurants use the same oil all day for their frying. A recent study found that the toxin 4-hydroxy-trans-2-nonenal (HNE) forms when common restaurant oils, such as canola, corn, soybean, and sunflower, are reheated. HNE has been connected to a higher risk of heart disease, stroke, Parkinson’s Disease and cancer.

Follow these guidelines (or, even better, reach for the goal of getting most of your nutrition from fresh, organic foods) and you will be on your way to significantly reducing your toxic load. And remember – when it doubt, throw it out!